Explosive type circuit breaker with frangible printed circuit board

ABSTRACT

An actuating device comprises a piston and cylinder unit having a piston with a metal forming configuration on the side thereof from which a piston rod projects, and a recess is provided in the rod adjacent the configuration. The arrangement is such that upon impact by that side of the piston on an end wall of the cylinder the material of the end wall is deformed into the recess to prevent rebound of the piston. The device is also illustrated in combination with an explosive operated initiating element.

United States Patent [1 1 [111 3,748,413 Sawyer July 24, 1973 EXPLOSIVETYPE CIRCUIT BREAKER 3,277,255 10/1966 Mattsson et al. ZOO/61.083,286,064 11/1966 Wilson et al ZOO/61.08 X RANGIBLE PRINTED ClRCUIT3,334,204 8/1967 Brenny et al 200/82 R 3,641,289 2/1972 DokopoulosZOO/61.08

Inventor: Robert H. Sawyer, Bernardsville,

Cartridge Actuated Devices, Inc., Fairfield, N.J.

Filed: Mar. 1, 1972 Appl. No.: 230,837

Assignee:

U.S. Cl. 200/6l.08, 200/82 R Int. Cl. 1101b 39/00 Field of SearchZOO/61.08, 82 R;

References Cited UNITED STATES PATENTS 4/1960 Leaman ZOO/61.08 X

Primary Examiner-4. R. Scott Attorney-Albert C. Nolte, Jr. et al.

[ 5 7 ABSTRACT 6 Claims, 2 Drawing Figures Pmmiumm ww w EXPLOSIVE TYPECIRCUIT BREAKER WITH FRANGIBLE PRINTED CIRCUIT BOARD From one aspect ofthis invention it is concerned with an actuating device, particularlyone including a piston and cylinder element which is subject to a highmotive force moving the piston from one position to another, but havinga small retaining force for holding the piston in that position. Fromthis aspect, it is an object of the invention to preclude rebound of thepiston from said other position against the small retaining force.

From another aspect, the invention is concerned with a piston cylindertype actuating device in combination with an explosively operatedinitiating device including a circuit breaking means, in whichcombination a common explosive charge operates said initiating deviceand said actuating device.

So far as the first aspect of this invention is concerned, the mostpertinent art of which applicant is aware is U. S. Pat. No. 3,234,727which issued on Feb. I5, 1966 to H. C. Filer. That patent shows anexplosively actuated motor comprising a piston and cylinder unit inwhich matching grooves are formed in the cylinder and in the piston anda deformable element is inserted into the cylinder between an end wallof the cylinder and the piston to be deformed upon actuation of themotor into the matching grooves thus to prevent rebound. The presentinvention provides an arrangement in which no groove is required in thecylinder wall, in which no assembly of a separate element between theend wall of the cylinder and the piston is required and which iseffective to prevent rebound.

Insofar as the second apsect of this invention is concerned, theapplicant is aware only of the material described in copendingapplication Ser. No. 230,622 filed Mar. 1, I972 in the name of John H.McPherson. The present invention embodies the device of theaforementioned application in combination with a piston cylinderactuating device and particularly in combination with a piston cylinderactuating device of the kind according to the first aspect of thisinvention.

An embodiment of this invention is illustrated in the accompanyingdrawings, in which:

FIG. 1 is a longitudinal cross section of a device according to thepresent invention; and

FIG. 2 is a detail of the device in FIG. 1 subsequent to actuation.

The .combination illustrated in the drawings comprises a circuitbreaking device generally indicated at and described fully in theaforementioned copending application. That device comprises a housing11, an anvil 12, a cutter 13, a plunger 14, and an explosive charge 15.Mounted between the anvil and cutter is a printed circuit board 16across which a circuit is made between a conductor 17 in the anvil and aconductor 18 in the cutter. The anvil is provided with an appropriaterecess 12' which receives the severed portion of the printed circuitboard after the device is actuated.

It is to be noted that that portion of the device 10 containing thecharge is closed by a washer element 20 which is held in position bycrimping over the edges 21 of the body 11. This aspect of the inventionand its relationship to the combination according to this invention willbe described in greater detail hereinafter.

The body 11 is externally screw threaded as at 30. By means of theseexternal screw threads 30, a cylindrical housing 50 is secured bycorresponding internal screw threads 51 to the device 10.

The housing 50 has a cylindrical internal space 52 and an end wall 53through which, and through an extension 54 of which, there is formed aguide opening 55. Mounted for sliding movement within the cylinder 52 isa piston comprising a head 60 and a rod or stem 62.

The head has an annular recess 64 formed in its generally cylindricalsurface and within that recess is an O- ring 66 which cooperates withthe walls of the cylindrical space 52 effectively to seal up the spacesof the cylinder to opposite sides of the piston head from each other.

The face 68 of the head constitutes a working face exposed to a motiveforce, which in this instance will be that resulting from the expansionof gases from the explosive charge 15 disposed in on explosive chargereceiving chamber. The opposite face 70 of the head has a preferablyannular metal deforming configuration 72. The metal deformingconfiguration 72 is, in this instance, of V-section defining a sharpedge 73 opposing the end wall 53 of the cylinder.

Adjacent to the configuration 73 and on the piston rod 62 is an annularrecess 76 which is defined in part by a shoulder 77 which faces thepiston surface 70 and the radially innermost face defining the V-sectionmetal forming configuration leads towards that recess.

The enlarged portion 78 of the piston rod coacts with the centralopening 55 of the end wall of the cylinder to guide the piston in itsmovement.

At the end of the piston rod, remote from the piston head, is aconfiguration which may be used for any actuating purpose, but isespecially useful for making or breaking a circuit (not shown)externally of the device. For example only, the configuration 90 may beformed as a contact shearing device similar to cutter 13, for cutting anexternal circuit, or it may be formed as a bridging contact for anexternal circuit. In addition the configuration 90 may be used to cut orshear diaphragms for the release of pressure or opening of one chamberinto another.

It will be appreciated that upon detonation of the charge 15, the pistonhead will be forcefully moved to the right, as viewed in FIG. 1, so thatthe edge 73 on face 70 of the piston head will strike the end wall ofthe cylinder. The material of the head and the material of the end wallof the cylinder, or the treatment of the forming configuration 72, orthe shaping of the end wall of the cylinder, are such that as the pistonstrikes the end wall of the cylinder the material of that end wall willbe swaged or deformed to move into the recess 76 and, by cooperationwith shoulder 77, prevent rebound of the piston from the end wall of thecylinder. The end wall of the cylinder may be of any suitable materialthat is swageable or deformable, such as a metallic material, while thematerial of the configuration 72 is preferably of a harder material.

By carefully selecting the firmness by which the washer 20 is crimped tothe end of housing I l relatively to the resistance of the printedcircuit board 16 to being sheared by cutter 13, one can arrange thateither piston 61 be moved to the right before the cutter is moved to theleft, or, that the cutter move to the left before the piston moves tothe right. In this way to achieve a make before break, or break beforemake" situation, where the configuration 90 at the outer end of thepiston controls a circuit.

While the cutting edge 73 of the present invention is illustrated asbeing annular, it is to be appreciated that it could take the form ofone or more teeth and be opposed to a recess in the piston rod ofsimilar configuration to swage only a part of the end wall of thecylinder into that recess. According to a further modification of thisinvention, the end of the wall of the cylinder may have an upstandingportion which may be turned over upon impact by the piston edge to moveinto the recess 76.

What is claimed is:

1. In combination, a housing enclosing a circuit breaking devicecomprising an anvil, a cutter cooperating with the anvil, a printedcircuit board between the anvil and cutter and including a circuitextending across a cutting edge of the cutter to be severed uponactivation of the cutter, and an explosive charge receiving chamberwithin the housing disposed to that side of the cutter remote from theanvil for activation of said cutter; and a piston and cylinder actuationunit within the housing and at the side of the chamber opposite to thecutter, said piston having a working face exposed to the force of thecharge on that side of the chamber remote from the cutter, and a pistonrod on its opposite face extending to the exterior of said housing andincluding an operating configuration exteriorly of the housing forperforming an operation exterior to the combination.

2. The combination of claim 1 wherein said piston working face isseparated from said charge by a releasable element closing said chamber,that one of the cutter and element having least resistance to movementupon detonation of said charge being first to be moved and thereafterthe other of said cutter and element being moved whereby said switchingof the circuit of said printed circuit board and the external operationmay be achieved sequentially.

3. The combination of claim 1 wherein said opposite face of said pistonhas a metal forming configuration and the piston rod adjacent said metalforming configuration has a recess defined at least in part by ashoulder disposed towards said opposite face of said piston whereby uponactuation of said device said metal forming configuration deformsmaterial of an opposite end wall of said cylinder into said recess toprevent rebound of said piston.

4. The combination of claim 2 wherein said opposite face of said pistonhas a metal forming configuration and the piston rod adjacent said metalforming configuration has a recess defined at least in part by ashoulder disposed towards said opposite face of said piston whereby,upon actuation of said device, said metal forming configuration deformsmaterial of an opposite end wall of said cylinder into saidrecess toprevent rebound of said piston' 5. Th combination of claim 2 whereinsaid releasable element comprises a disk releasably secured in anopening to said chamber.

6. The combination of claim 5 wherein said disk is crimped to the end ofsaid chamber.

1. In combination, a housing enclosing a circuit breaking devicecomprising an anvil, a cutter cooperating with the anvil, a printedcircuit board between the anvil and cutter and including a circuitextending across a cutting edge of the cutter to be severed uponactivation of the cutter, and an explosive charge receiving chamberwithin the housing disposed to that side of the cutter remote from theanvil for activation of said cutter; and a piston and cylinder actuationunit within the housing and at the side of the chamber opposite to thecutter, said piston having a working face exposed to the force of thecharge on that side of the chamber remote from the cutter, and a pistonrod on its opposite face extending to the exterior of said housing andincluding an operating configuration exteriorly of the housing forperforming an operation exterior to the combination.
 2. The combinationof claim 1 wherein said piston working face is separated from saidcharge by a releasable element closing said chamber, that one of thecutter and element having least resistance to movement upon detonationof said charge being first to be moved and thereafter the other of saidcutter and element being moved whereby said switching of the circuit ofsaid printed circuit board and the external operation may be achievedsequentially.
 3. The combination of claim 1 wherein said opposite faceof said piston has a metal forming configuration and the piston rodadjacent said metal forming configuration has a recess defined at leastin part by a shoulder disposed towards said opposite face of said pistonwhereby upon actuation of said device said metal forming configurationdeforms material of an opposite end wall of said cylinder into saidrecess to prevent rebound of said piston.
 4. The combination of claim 2wherein said opposite face of said piston has a metal formingconfiguration and the piston rod adjacent said metal formingconfiguration has a recess defined at least in part by a shoulderdisposed towards said opposite face of said piston whereby, uponactuation of said device, said metal forming configuration deformsmaterial of an opposite end wall of said cylinder into said recess toprevent rebound of said piston.
 5. Th combination of claim 2 whereinsaid releasable element comprises a disk releasably secured in anopening to said chamber.
 6. The combination of claim 5 wherein said diskis crimped to the end of said chamber.